Pathogens Distribution And The Changes Of Bacterial Resistance For Ventilator-associated Pneumonia: A Retrospective Clinical Study

OBJECTIVE To investigate the characteristics of pathogens and high-risk factors of ventilator-associated pneumonia (VAP) in the people's hospital of Tongling city,Anhui,and to explore the antimicrobial resistance of predominant pathogens in last 10 years. To provide the prevention strategies and the reasonable antimicrobial strategy based on the local distribution of pathogens.METHODS A retrospective study of total 538 cases with VAP were collected for analyzing in 1236 mechanical ventilation(>48h) patients from June 1996 to June 2006.The Pathogens distribution and the changes of bacterial resistance were compared from June 1996 to June 2001 with from July 2001 to June 2006,respectively. Standard disk diffusion susceptibility tests were performed on the predominant pathogens.RESULTS During this period, the incidence of VAP was 44.34%, 304 cases were infected by two or more pathogens ( 538 VAP cases) . The occurrence of VAP in high-risk factors include the following: older(≥60 years), and been admitted to ICU, more than one weeks of the H-2 receptor inhibitors and glucocorticoids,and the establishment of artificial airway. There is no significant difference on the occurrence of VAP between oral/nasal endotracheal intubation group and tracheotomy group (χ~2 = 2.641, P = 0.104).The main pathogens of VAP were Gram negative organisms (68.63%) whose predominant pathogens were Pseudomonas aeruginosa and Acinetobacter. On the other hand, 75.40% of Gram positive organisms were Staphylococcus epidermidis.Of the pathogens 20.98% were eumycetes. Compared from June 1996 to June 2001 with from July 2001 to June 2006,there was no significant difference on the incidence rate of P.aeruginosa(31.76% vs 31.58%).During the recent 10 years,the incidence of Acinetobacter rose up from 8.23% to 15.23% and the rate of oxacillin-resistant Staphylococcus epidermidis rose up from 18.75% to 71.43%. The sensitivity of P.aeruginosa and Acinetobacter isolates descended to sodium imipenem cilastatin and ceftazidime in past 10 years.CONCLUSIONS The main Gram negative pathogens of VAP in our hospital were P.aeruginosa and Acinetobacter, and an remarkable changes in pathogens distribution and infection spectrum had been taken place during the past 10 years.The selection of initial experimental antimicrobial strategy will face a great challenge.